Heat exchangers are used to exchange heat between two fluids. In one example, heat may be transferred from a first fluid to a second fluid, such as from air to a coolant in a liquid-cooled heat exchanger. As a result, the temperature of the coolant may increase. If the coolant temperature increases to a high enough level, boiling of the coolant may occur within the heat exchanger and possibly result in heat exchanger degradation. Engines may utilize heat exchangers such as an exhaust gas recirculation (EGR) cooler, used to reduce the temperature of recirculated exhaust gas before it enters an intake passage of the engine. In one example, the temperature of an engine coolant circulating through the EGR cooler may increase above a threshold level, increasing the likelihood of boiling within the cooler. As such, EGR cooler degradation may increase.